An estimated 80,000 American prisoners spend 23 hours a day in closed isolation units for 10, 20 or even more than 30 years.

Now, amid growing evidence that it causes mental breakdown, the Federal Bureau of Prisons has decided for the first time to review its policies on solitary confinement.

Eastern State Penitentiary in Philadelphia, which pioneered solitary confinement, is a castle of a prison that was meant to reform incarceration itself when it opened in 1829. The idea behind the prison's solitary confinement areas was to use sensory deprivation to reform inmates. The thought was that the isolation and quiet would free the innately good soul.

"They believed that isolation here was going to bring about the best of these inmates. Change them for life. Make them penitent," says Sean Kelley, director of public programming at the historic site. "There is a lot of evidence that that is not what happened."

For many reasons that sound familiar today – including cost and questionable effectiveness — Eastern State dropped the practice in 1913, but by then the blueprint of this penitentiary had been copied more than 300 times across the Western world. The prison, once a state-of-the-art facility, closed its doors in 1970, and is now a museum.

An Uncertain Method

Solitary confinement exploded with the law-and-order policies of the 1980s, when almost every state built what's called a "supermax" for the so-called "worst of the worst." But since then, more questions have been raised about the mental health of prisoners held this way.

Last summer, Sen. Dick Durbin, D-Ill., chair of the Constitution, Civil Rights and Human Rights subcommittee, led hearings to address solitary confinement practices. He says it was prompted by a New Yorker article by Boston surgeon Atul Gowande titled "Hellhole."

"I read it, and I couldn't forget it," Durbin tells Jacki Lyden, host of weekends on All Things Considered. "It was all about the impact of segregation and isolation on prisoners, and I started thinking about it as part of my agenda for my subcommittee on human rights."

Testifying in front of the committee was Charles Samuels, director of the Federal Bureau of Prisons. Samuels explained the necessity of the solitary confinement to keep violent inmates apart from guards and other prisoners.

"The use of any form of restricted housing, however limited, remains a critical management tool that helps us maintain safety, security and effective reentry programming for all federal inmates," Samuels said.

The BOP wouldn't grant an interview for this story, but provided a comment saying the bureau is confident the review "will highlight both the strengths that the Bureau brings to corrections management, as well as innovative ideas from the states."

Solitary confinement already doubles to triples the costs of incarceration, up to $60,000 a year per inmate. But wardens who've seen its wide use now in the last 30 years have their own evaluation of whether it does more harm than good.

"I really believed when I got close to the situation at the supermax in Wisconsin that one of the things that I was seeing was mentally ill people who didn't come in mentally ill," says Walter Dickey, formerly the secretary of corrections for Wisconsin.

Dickey tells NPR's Lyden that the level of security and the overcrowding he saw were detrimental to a prisoner's mental health, even when they didn't start out in isolation. He doesn't, however, think the practice should be dropped.

"[The feds] had experiences in which they had inmates kill multiple staff members and multiple inmates," he says. "People like that need to be isolated, at least temporarily, if not for a longer period of time until you can release them into the population, the general population, with some confidence that they're not going to do severe damage to other people."

At the hearing, Durbin noted that after Mississippi had done away with solitary confinement, prison violence went down by 50 percent and the cost of incarceration went down as well.

"It was a wake-up call to all of us to take a hard look at it," he says. "Maybe this just isn't the best way to deal with these problems."

Living Through Isolation

As prisoners testify about suicidal depression, self-mutilation, lethargy, hallucinations and other ills, more attention is being paid to inmates who have lived through the extreme, often uncertain isolation.

Robert King is one of the Angola Three — one of the men serving the longest sentences in the country in solitary confinement — in his case at Angola State Penitentiary in Louisiana. King was released in 2001, after serving 29 years in solitary, at times in a 3-by-6 cell that he describes as a "tomb."

"There was a slab of concrete that you slept on ... and during the winter time you froze, and during the summer time you overheated," King says.

During his time in prison, King says he saw the system, and the solitary confinement, change people. He says he saw once open people become more withdrawn as time went on.

"I kind of insulated myself when I saw what happened to them; I think it created a steel resolve in myself to not succumb to that," he says.

After his release, King published a book, and he also speaks internationally, but despite his post-incarceration success, he says the effects of his solitary confinement still lingers.

"I don't think a person could get dipped in waste and not come up smelling," he says. "Even though it may not be totally apparent, the impact and the effects are there."

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JACKI LYDEN, HOST:

From NPR News, this is WEEKENDS on ALL THINGS CONSIDERED. I'm Jacki Lyden. In this hour, celebrating the life of Aldo Leopold, the father of modern conservation; and too many Ph.D.s in the sciences. First, though, an estimated 80,000 American prisoners spend 23 hours a day in closed isolation cells for 10, 20, even more than 30 years. Now, amid growing concerns over the policy, the Federal Bureau of Prisons has decided, for the first time in its history, to review its policies on solitary confinement. That's our cover story.

(SOUNDBITE OF MUSIC)

LYDEN: When Charles Dickens visited the United States of America this very week in 1842, the two places he most wanted to see were the falls at Niagara, and a castle of a prison meant to reform incarceration itself - Eastern State Penitentiary, in Philadelphia. Eastern State Penitentiary pioneered solitary confinement for every inmate, back in 1829. This past week, we went there too.

(SOUNDBITE OF LOCKS BEING OPENED)

SEAN KELLEY: Boy, it really is a bleak day here. We didn't use to open the building in winter at all because it's truly a ruin.

LYDEN: Sean Kelley, director of public programming, took us through the halls of the historic prison, now a museum. It's been preserved in a state of evocative ruin. Corridors of isolation cells radiate out like the spokes of a wheel, around a rotunda like an omniscient eye. Eastern State's first inmate was an 18-year-old African American named Charles Williams, who served two years here for stealing a watch and a gold key. Sensory deprivation was intended to reform the soul. Inmates were hooded; guards wore socks over their shoes; books weren't allowed. Redemptive? Kelley tells me Dickens didn't think so.

KELLEY: He said, "I hold the slow and daily tampering with the mysteries of the brain to be immeasurably worse than any torture of the body."

LYDEN: But it would be decades before Eastern State authorities changed the policy.

KELLEY: They believed that this isolation here was going to make - bring out the best in these inmates; change them for life, make them penitent.

LYDEN: And is there any evidence that that is indeed what happened?

KELLEY: There's a lot of evidence that that is not what happened.

LYDEN: The high cost, the questionable effectiveness, and the need for more cells led Eastern State Penitentiary to end solitary confinement by 1913. Unfortunately, by then, the practices - even the blueprint of this prison - had been copied more than 300 times around the world.

(SOUNDBITE OF MUSIC)

LYDEN: In 1970, Eastern State Penitentiary, by then antiquated and overcrowded, closed its last cell door. That same year, a young man - Robert King - was convicted for robbery and taken into custody at Angola state prison in Louisiana, beginning a sentence there that would last 32 years; 29 of them, in solitary.

ROBERT KING: You was in a 6-by-9-by-12-foot cell. You got an hour out to shower. And then after that, you were locked up all the rest of the days.

LYDEN: We'll talk to Robert King later on. But let's go back to last summer - of 2012 - when Sen. Dick Durbin, of Illinois, convened a hearing.

(SOUNDBITE OF ARCHIVED RECORDING)

SEN. DICK DURBIN: Good morning. This hearing of the Subcommittee on the Constitution, Civil Rights and Human Rights...

LYDEN: Solitary confinement exploded with the law-and-order policies of the 1980s, when 40 states built what's called a supermax prison in which each prisoner is held in solitary. Since then, more questions have been raised about the mental health of prisoners incarcerated this way. Sen. Durbin is, by now, convinced it's a violation of the Eighth Amendment against cruel and unusual punishment.

So are you prepared to say that this does constitute a violation of the Eighth Amendment against cruel and unusual punishment?

DURBIN: I can tell you that in the extreme, it most certainly does.

LYDEN: Testifying in front of the committee was the director of the Federal Bureau of Prisons, Charles Samuels. Samuels explained the necessity of the practice, to keep violent inmates apart from guards and other prisoners. And he read from a statement.

CHARLES SAMUELS: The use of any form of restricted housing, however limited, remains a critical management tool that helps us maintain safety, security and effective re-entry programming for all federal inmates.

LYDEN: Solitary confinement doubles or triples the costs of incarceration - up to $60,000 a year per inmate. But corrections officials who've seen its wide use now, for the last several decades, have their own evaluation of whether it does more harm than good. Here's Walter Dickey, formerly the secretary of corrections for Wisconsin.

WALTER DICKEY: I really believed, when I got close to the situation at the supermax in Wisconsin, that one of the things that I was seeing was mentally ill people who didn't come in mentally ill. But the level of security - frankly, the overcrowding, even when they didn't start out in segregation, was very detrimental to their mental health, and led them to act in ways that led them to get tickets. And tickets got them into segregation.

LYDEN: Tickets for small things lead to more segregation time; it can be an endless cycle. But Dickey says the practice should be reserved for really violent offenders.

DICKEY: People like that need to be isolated at least temporarily, if not for a longer period of time, until you can release them into the population - the general population, with some confidence that they're not going to do severe damage to other people.

LYDEN: Increasingly, former solitary prisoners are testifying to suicidal depression, self-mutilation, lethargy, hallucinations and other ills. At the time of his release in 2001, Robert King had been among the longest-serving solitary inmates in the country - 29 years. Together with two other men - Herman Wallace and Albert Woodfox - he's one of the Angola Three, serving over a hundred years between the three of them. They've sued the state of Louisiana, but King's co-plaintiffs remain in solitary confinement.

KING: The cells were pretty bad. And they were maybe about - maybe 3 feet wide, and about 6 feet long. It's almost like you was in a tomb, and there was a slab of concrete that you laid on, that you slept on. And you ate for breakfast, for a meal - you had three meals a day. You had two slices of bread each meal. During the wintertime, you froze. And during the summertime, you was overheated. And - but in any event, you were starved.

LYDEN: I'd like to know about your time in solitary, when you're in this CCR unit - this closed restriction unit. What was a typical day like? Could you tell me?

KING: For me, it spanned three decades. So initially, when we went to CCR, you know, you were allowed any number of books. And if you could afford a radio, that was allowed. You was in a 6-by-9-by-12-foot cell. You got an hour out to shower. And after that, you were locked up all the rest of the days. They brought your meals to your cell.

I mean, that practice continued except that it was kind of modified a little bit at a certain point, depending on whichever administration came in because over that period of time, you have a number of people going and coming. At one time - like I said - we were allowed any number of books. But it come a period of time - or came a period of time when they kind of minimized that to six books. In fact, well, you could say four because there - a dictionary and a Bible was something - was considered one of the books that you would have; you was allowed to have four other books. And at one point, we wasn't allowed to go in the yard. We had to file a lawsuit to get on the yard. It was seven years I was in CCR before I set foot on any soil.

LYDEN: Let me ask you about your mental health and also - you know, what you saw other prisoners go through, in terms of their mental health because you have had, by any measure, a very productive post-prison career. You've been a writer, a speaker internationally. But did everybody get through? I mean, how difficult was it for you to keep your thoughts together?

KING: (Exhales swiftly) I am telling you, it wasn't easy because - you know, I did see people come in; and I saw how open they were and then how, after a while, they become withdrawn. And I kind of insulated myself, when I saw what happened to them. I think it created a resolve - a steel resolve in myself, you know, to not to succumb to that.

So my thoughts - I used to love to think, and I used to love to write. I used to love to exercise. I would - time just didn't matter to me anymore but - except one thing: the time that I would, you know, utilize to try to get out of prison.

LYDEN: I asked him if he thinks about his friends and co-plaintiffs who are still inside - Wallace and Woodfox.

KING: Well, I do. I think about them a lot. April 17th will be 41 years that both have been held in solitary-like conditions in Angola. So it'll be 41 years. You know, I think about that. I was there for 29. And when I think about how much longer they have been there, it'll be like - what? - 12 years longer than I was.

And you know, people ask me this - the question all the time, well, why ain't you crazy, you know. And I just kind of laugh, you know. I let them know that, I didn't tell you I wasn't crazy, you know? I don't think a person could get dipped in waste and not come up smelling. And even though it may not be totally apparent, the impact and the effects are there.

LYDEN: One of the most stated reasons for long-term isolation is that it controls open-prison populations. Sen. Durbin noted just the opposite - that when Mississippi lowered its use of solitary confinement, violence reduced.

DURBIN: Prison violence went down by 50 percent, and the cost of incarceration went down. It was a wake-up call to all of us, to take a hard look at it. Maybe this just isn't the best way to deal with these problems.

LYDEN: And here's another sobering thought...

(SOUNDBITE OF DOOR SLAMMING SHUT)

LYDEN: Standing, locked alone in one of the old, monk-like isolation cells at Eastern State Penitentiary, the feeling is of being adrift on an ice floe. The light comes from a shaft overhead, like an igloo. There's no window, no horizon. Almost 70,000 people passed through Eastern State Penitentiary before it closed its doors as a prison, over 40 years ago. That's fewer than the number of people in solitary confinement in America today, the most anywhere in the world. And most of them will one day rejoin society, ready or not.